class/WindowsBase/System.Windows.Threading/DispatcherTimer.cs

   1 // Permission is hereby granted, free of charge, to any person obtaining
   2 // a copy of this software and associated documentation files (the
   3 // "Software"), to deal in the Software without restriction, including
   4 // without limitation the rights to use, copy, modify, merge, publish,
   5 // distribute, sublicense, and/or sell copies of the Software, and to
   6 // permit persons to whom the Software is furnished to do so, subject to
   7 // the following conditions:
   8 //
   9 // The above copyright notice and this permission notice shall be
  10 // included in all copies or substantial portions of the Software.
  11 //
  12 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  13 // EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  14 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  15 // NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  16 // LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  17 // OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  18 // WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
  19 //
  20 // Copyright (c) 2006 Novell, Inc. (http://www.novell.com)
  21 //
  22 // Authors:
  23 //      Miguel de Icaza (miguel@novell.com)
  24 //
  25 using System;
  26 using System.Collections;
  27 using System.Threading;
  28
  29 namespace System.Windows.Threading {
  30
  31         public class DispatcherTimer {
  32                 DispatcherPriority priority;
  33                 Dispatcher target_dispatcher;
  34                 long interval;
  35                 EventHandler callback;
  36                 Timer timer;
  37                 object tag;
  38
  39                 public DispatcherTimer ()
  40                         : this (DispatcherPriority.Background, Dispatcher.CurrentDispatcher)
  41                 {
  42                 }
  43
  44                 public DispatcherTimer (DispatcherPriority priority)
  45                         : this (priority, Dispatcher.CurrentDispatcher)
  46                 {
  47                 }
  48
  49                 public DispatcherTimer (DispatcherPriority priority, Dispatcher dispatcher)
  50                         : this (TimeSpan.Zero, priority, null, dispatcher)
  51                 {
  52                 }
  53
  54                 public DispatcherTimer (TimeSpan interval, DispatcherPriority priority,
  55                                         EventHandler callback, Dispatcher dispatcher)
  56                 {
  57                         this.priority = priority;
  58                         this.target_dispatcher = dispatcher;
  59                         this.interval = interval.Ticks;
  60                         this.callback = callback;
  61                 }
  62
  63                 public void Start ()
  64                 {
  65                         if (timer == null){
  66                                 long repeat_interval = interval;
  67                                 if (repeat_interval == 0)
  68                                         repeat_interval = 1;
  69                                 timer = new Timer (new TimerCallback (timer_tick), null, interval, repeat_interval);
  70                         }
  71                 }
  72
  73                 void timer_tick (object state)
  74                 {
  75                         target_dispatcher.BeginInvoke (priority, (ThreadStart) delegate {
  76                                 EventHandler h = Tick;
  77                                 if (h != null)
  78                                         h (this, EventArgs.Empty);
  79                                 if (callback != null)
  80                                         callback (this, EventArgs.Empty);
  81                         });
  82                 }
  83
  84                 public void Stop ()
  85                 {
  86                         if (timer == null)
  87                                 return;
  88
  89                         timer.Dispose ();
  90                         timer = null;
  91                 }
  92
  93                 public Dispatcher Dispatcher {
  94                         get {
  95                                 return target_dispatcher;
  96                         }
  97                 }
  98
  99                 public TimeSpan Interval {
 100                         get {
 101                                 return new TimeSpan (interval);
 102                         }
 103
 104                         set {
 105                                 if (interval == value.Ticks)
 106                                         return;
 107
 108                                 interval = value.Ticks;
 109
 110                                 if (timer != null)
 111                                         timer.Change (interval, interval);
 112                         }
 113                 }
 114
 115                 public bool IsEnabled {
 116                         get {
 117                                 return timer != null;
 118                         }
 119
 120                         set {
 121                                 if (value && timer == null)
 122                                         Start ();
 123                                 if (value == false && timer != null)
 124                                         Stop ();
 125                         }
 126                 }
 127
 128                 public object Tag {
 129                         get {
 130                                 return tag;
 131                         }
 132
 133                         set {
 134                                 tag = value;
 135                         }
 136                 }
 137                 public event EventHandler Tick;
 138         }
 139 }